Container sealing apparatus

ABSTRACT

Container sealing apparatus for heat sealing a plastics web to openings of containers. The apparatus comprises a transport system for transporting containers along a pair of feed paths extending alongside one another; a sealing system through which the feed paths extend, the sealing system being adapted to seal openings of containers with the plastics web material; and pairs of unwind and wind up mandrels associated with each feed path for supporting spools of the plastics material. A web of the plastics material extends in use from a spool on the unwind mandrel to a spool on the wind up mandrel of each pair and through the sealing system, wherein each mandrel is movable between a working position in which it extends orthogonally to the transport direction and a loading position at which spools of the web material can be loaded on or unloaded from the mandrel.

SUMMARY OF INVENTION

The invention relates to a container sealing apparatus for heat sealing a plastics web to openings of containers and to a packaging system comprising such container sealing apparatus.

DESCRIPTION OF THE PRIOR ART

Known container sealing apparatus comprises a transport system for transporting containers along a feed path; a sealing system through which the feed path extends, the sealing system being adapted to seal openings of containers with a plastics web material; and a pair of unwind and wind up mandrels associated with the feed path for supporting spools of the plastics material whereby a web of the plastics material extends in use from a spool on the unwind mandrel to a spool on the wind up mandrel and through the sealing system.

This known container sealing apparatus is often used in food packaging applications, for example the packaging of raw or precooked food into trays and other shaped containers.

A typical food packaging factory will utilise several lines of such container sealing apparatus, each associated with a food delivery system, for delivering measured quantities of food into open containers or trays, sealing the trays, and then packing the sealed trays into boxes. There is a need to increase the throughput of the packaging process in order to increase the number of containers that are filled and sealed per hour. However, a typical food packaging line takes up a significant amount of space in view of the need to provide a food delivery system such as a combinational weigher, the container sealing apparatus, and some form of packaging apparatus for packing the sealed containers into boxes.

One approach is to try and speed up the apparatus but there are limitations on the speed with which food or other items can be weighed and supplied to containers, heat sealing time required and the like.

SUMMARY OF THE INVENTION

In accordance with the present invention, we provide a container sealing apparatus for heat sealing a plastics web to openings of containers, the apparatus comprising a transport system for transporting containers along a pair of feed paths extending alongside one another; a sealing system through which the feed paths extend, the sealing system being adapted to seal openings of containers with the plastics web material; and an unwind mandrel associated with each feed path for supporting a spool of the plastics material whereby a web of the plastics material extends in use from a spool on the unwind mandrel through the sealing system to a waste location, wherein each mandrel is movable between a working position in which it extends orthogonally to the transport direction and a loading position at which spools of the web material can be loaded on or unloaded from the mandrel.

We have realised that it is possible to achieve increased throughput by combining a pair of single lane systems. There is a problem with simply providing two conventional single lane systems side-by-side since to do this does not save significant space, We have realised that the main reason for this is that it is necessary to have access to the mandrels on which the spools of plastic material are mounted in order to be able to load and unload those spools. It would be feasible to provide mandrels which are supported at their laterally inner ends but then those supporting mechanisms will in themselves prevent the two lanes from being placed close together and achieve an optimised footprint. Consequently, instead, the apparatus according to the invention provides that each mandrel is moveable from its working position to a loading position at which it can be loaded and unloaded (without needing to obtain access between the feed paths or lanes).

Preferably, wind up mandrels are positioned at the waste locations for winding up waste plastics web material, each windup mandrel being movable between a working position in which it extends orthogonally to the transport direction and a loading position at which spools of the web material can be loaded on or unloaded from the mandrel. However other waste systems could be used.

Preferably, each unwind and windup mandrel is movable between its working and loading positions about a vertical axis. This is most conveniently achieved by mounting each mandrel to a respective axle rotatable about the vertical axis.

Other mounting arrangements are also possible, for example a slide mounting in which each mandrel can slide between its working and loading positions.

Where the unwind and windup mandrels are mounted to respective axles, preferably each axle is located at a laterally outward position with respect to the associated feed path, such that the mandrel mounted to the axle projects laterally inwards in its working position. The advantage of this arrangement is that the axles do not interfere with the ability to place the two paths as close together as possible and thus minimise the footprint of the apparatus.

Preferably, the apparatus further comprises a locking mechanism to lock each mandrel at least in its working position and most preferably the mandrels can be locked in each position.

The sealing system can comprise any conventional heat sealing system known in the art but typically comprises one or more heated plates located above the feed paths and apparatus for bringing the heated plate(s) into contact with the plastics material so as to heat seal the plastics material to the containers.

The sealing system can comprise a common heated plate and support tools for conveying containers into contact with the plastics material and the heated plate or independently operable heated plates and support tools.

BRIEF DESCRIPTION OF THE DRAWINGS

An example of container sealing apparatus according to the invention will now be described with reference to the drawings, in which:

FIG. 1 is a perspective view of an example of the container sealing apparatus in a tray sealing line;

FIG. 2 is an enlarged perspective view of the container sealing apparatus shown in FIG. 1;

FIG. 3 is a side elevation of the container sealing apparatus with the side covers removed;

FIG. 4 is a schematic, perspective view of parts of the container sealing apparatus;

FIG. 5 is a perspective view of part of the container sealing apparatus, with the covers raised and the unwind mandrel in its working position;

FIG. 6 is a view similar to FIG. 5 but with the unwind mandrel in its loading position;

FIG. 7 is a detailed perspective view of the plastics web spool mounting apparatus;

FIG. 8 is a cross-section through the apparatus shown in FIG. 7;

FIG. 9 is a view similar to FIG. 7 but taken from a different direction and omitting the mandrel;

FIGS. 10 and 11 are perspective views showing the spool mounting apparatus during movement between its working position and loading/unloading position; and

FIG. 12 is a perspective view of the spool mounting apparatus (with the mandrel omitted) in the loading/unloading position.

DETAILED DESCRIPTION OF EMBODIMENT

FIG. 1 is a perspective view of a dual lane food packaging system 10 comprising two feed paths or packaging lanes 12A 12B extending alongside each other in a feed direction 14, feed path or lane 12A being to the left of feed path 126. The apparatus comprises a number of modules arranged sequentially along the feed paths. These modules comprise a filling module 16, a container or tray sealing module 18, a quality control unit module 20, and a packing module 22. Each of the modules comprises sets of side plates 24 which are hinged so that they can be retracted to allow access to the modules or extended (as shown) when the system is in use.

Each of the feed paths 12A, 12B is defined by sets of conveyor belts extending through the modules 16-22 in parallel, two of the belts being indicated in FIG. 1 at 26A, 26B respectively.

The filling module 16 comprises a conventional multi-head weigher 202 of the kind manufactured and sold by Ishida Company Limited of Japan, the weigher being supplied with food product via a supply conveyor 204. Food product, after weighing, is then supplied into respective, open top trays (not shown) carried by the conveyors of the respective feed paths of 12A, 12B passing underneath the weigher. Typically, the weigher has a pair of supply chutes (not shown) which are directed towards the respective conveyors of the paths 12A,12B. The trays may be provided on the conveyors manually or automatically using a robotic tool or the like.

The filled trays are then conveyed by the conveyors of the feed paths 12A, 12B into the container sealing module 18 where plastics film is heat sealed onto each container to close it as will be described in more detail below.

The sealed containers are then conveyed by conveyors 26A, 26B into the quality control module 20 in which conventional tests are carried out including seal inspection, label inspection, x-ray inspection, check weighing and the like. The sealed trays are then supplied to the packaging module 22 where they are packed into boxes or crates for shipping.

The container sealing module 18 is shown in more detail in FIGS. 2 to 6. The module 18 has the same components on each side, corresponding to the respective feed lanes 12A, 12B and so in general will only be described with reference to one of the feed lanes 12B.

The container sealing module 18 has three sections 50, 52, and 54 arranged sequentially in the direction 14. Trays arrive at the entrance section 50 on respective belts 56, 58 (corresponding to feed lanes 12A, 12B). After a group of trays has been supplied to the respective belts 56, 58 within the section 50, the belts are stopped from moving and respective gripper arms (not shown) transfer the group of trays from the belts 56, 58 onto respective lower tool halves 60A, 60B within the central sealing section 52. Once located on the lower tool halves 60A, 60B, these tool halves are then independently moved in an upward direction until the upper edges of the trays contact a sealing film (to be described below) and an upper tool half 62A, 62B which is heated. This movement is caused by activating motor driven lift screws or the like (not shown). The lower tool halves 60A, 60B are then returned to the position shown in FIGS. 3 and 4 once the plastics film has been heat sealed to the trays. The gripper arms are then activated to move the sealed trays onto respective stationary conveyors 64A, 64B in the third section 54. Once the trays are located on the conveyors 64A, 64B, these conveyors are activated to transfer the trays onward to conveyors 26A, 26B to transfer the trays to the quality control module 20 and on to the packaging module 22.

As can be seen most clearly in FIG. 4, the container sealing module 18 includes a pair of tray guides 70A, 70B associated with the feed lanes 12A, 12B respectively. These can be adjusted laterally via mechanisms 72A, 726 depending upon the width of the trays being processed.

Control computers 74, 76 synchronise operation of the gripper arms and the tray guides.

Plastics film to be heat sealed to the containers is supplied in web form from a supply spool 100 mounted on a supply mandrel 102 in the section 54 through the sealing section 52 to a take up spool (not shown) mounted on a take up mandrel 104 at a waste location in the section 50. In some cases the film can be wound directly on the mandrel while in other cases the film may be collected in another manner, for example piled up in a collection bin. The film is guided by various idler rollers (not shown) and passes under the upper tool half 62B but spaced therefrom until it is brought into contact with the containers during the sealing operation. The film is supplied from the supply spool 100 and taken up by the take-up spool by causing incremental rotation of the mandrels 102, 104. This occurs under control of the control apparatus 74. Alternatively, the take-up spool mandrel 104 alone could be rotated to draw film off the supply spool.

Each of the mandrels 102, 104 in association with each lane 12A, 12B is mounted in a similar manner and so the mounting of the supply spool mandrel 102 of feed lane 126 only will be described in more detail with respect to FIGS. 5 and 6. As can be seen in these drawings, the mandrel 102 is rotatably mounted to a vertically extending axle 150 formed by a hollow conduit. The mandrel can be swung through 90 degrees about the vertical axis from its working position (FIG. 5) to its unloading/loading position (FIG. 6).

FIGS. 7-12 illustrate the mounting arrangement of the mandrel in more detail.

As can be seen in FIGS. 7 and 8, the mandrel 102 is rotatably mounted on the end of a cylindrical housing 155 located at the end of a hollow conduit 152 connected at its opposite end to a cylindrical barrel 154. A mandrel drive motor 300 is mounted in the conduit 152 and coupled via gears 302, 304 to the mandrel 102. The barrel 154 has an axle 156 extending upwardly into a bearing 158 in an upper flange 160 of a mount 162 secured to the frame of the sealing apparatus.

The lower end of the barrel 154 is cylindrically formed and secured in a bearing 164 of a lower flange 166 of the mount 162. The lower part of the barrel opens into the axle or conduit 150.

An o-ring seal 168 is mounted between the barrel 154 and the conduit 150 to protect the motor and control cables from ingress of water. This also has the advantage of achieving a very clean exterior design for good water and hygiene performance.

The outer surface of the barrel 154 is provided with a first roller 170 (FIG. 9) which, in the working position of the mandrel 102 (FIG. 9) is located in a camtrack feature 172 formed in a wall 174 of the mount 162. As can be seen more clearly in FIG. 10, the camtrack feature 172 includes an indent 176 in which the roller 170 sits when the mandrel 102 is in the working position.

In order to move the mandrel 102 to its loading/unloading position (FIG. 6) the arm 152 is manually pulled by the operator to cause it to rotate about the vertical axis. This force causes the first roller 170 to ride up out of the indent 176 (FIG. 10) and to move out of the camtrack feature 172 (FIG. 11) while a second roller 180 also mounted to the barrel 154 starts to enter the camtrack feature 172 (FIG. 11) until it sits in the indent 176 (FIG. 12). At this point, the mandrel 102 is located in its loading/unloading position,

In order to prevent the barrel 154 from being rotated by more than 90 degrees, an upstanding peg 182 is mounted to the upper surface of the barrel 154 received in a circumferentially extending slot 184 such that the peg 182 abuts against one or other end of the slot 184 depending upon the position of the arm 152. 

I claim:
 1. Container sealing apparatus for heat sealing a plastics web to openings of containers, the apparatus comprising a transport system for transporting containers along a pair of feed paths extending alongside one another; a sealing system through which the feed paths extend, the sealing system being adapted to seal openings of containers with the plastics web material; and an unwind mandrel associated with each feed path for supporting a spool of the plastics material whereby a web of the plastics material extends in use from a spool on the unwind mandrel through the sealing system to a waste location, wherein each mandrel is movable between a working position in which it extends orthogonally to the transport direction and a loading position at which spools of the web material can be loaded on or unloaded from the mandrel.
 2. Apparatus according to claim 1, wherein each mandrel is movable between its working and loading positions about a substantially vertical axis.
 3. Apparatus according to claim 2, wherein each mandrel is mounted to a respective axle for rotation about a vertical axis.
 4. Apparatus according to claim 2, wherein each axle is located at a laterally outward position with respect to the associated feed path, such that the mandrel mounted to the axle projects laterally inwards in its working position.
 5. Apparatus according to claim 1, further comprising a locking mechanism to lock each mandrel at least in its working position.
 6. Apparatus according to claim 1, wherein said sealing system comprises one or more heated plates located above the feed paths and apparatus for bringing the heated plate(s) into contact with the plastics material so as to heat seal the plastics material to the containers.
 7. Apparatus according to claim 6, wherein said sealing apparatus includes a support tool for conveying containers into contact with the plastics material and the heated plate(s).
 8. Apparatus according to claim 7, wherein each feed path is associated with an independently operable heated plate and support tool.
 9. Apparatus according to claim 1, further comprising wind up mandrels positioned at the waste locations for winding up waste plastics web material, each windup mandrel being movable between a working position in which it extends orthogonally to the transport direction and a loading position at which spools of the web material can be loaded on or unloaded from the mandrel.
 10. Apparatus according to claim 9, wherein each windup mandrel is movable between its working and loading positions about a substantially vertical axis.
 11. Apparatus according to claim 10, wherein each windup mandrel is mounted to a respective axle for rotation about a vertical axis,
 12. Apparatus according to claim 10, wherein each axle is located at a laterally outward position with respect to the associated feed path, such that the windup mandrel mounted to the axle projects laterally inwards in its working position.
 13. Apparatus according to claim 9, further comprising a locking mechanism to lock each mandrel at least in its working position.
 14. Apparatus according to claim 9, wherein said sealing system comprises one or more heated plates located above the feed paths and apparatus for bringing the heated plate(s) into contact with the plastics material so as to heat seal the plastics material to the containers.
 15. Apparatus according to claim 14, wherein said sealing apparatus includes a support tool for conveying containers into contact with the plastics material and the heated plate(s).
 16. Apparatus according to claim 15, wherein each feed path is associated with an independently operable heated plate and support tool.
 17. A packaging system comprising container sealing apparatus comprising a transport system for transporting containers along a pair of feed paths extending alongside one another; a sealing system through which the feed paths extend, the sealing system being adapted to seal openings of containers with the plastics web material; and pairs of unwind and wind up mandrels associated with each feed path for supporting spools of the plastics material whereby a web of the plastics material extends in use from a spool on the unwind mandrel to a spool on the wind up mandrel of each pair and through the sealing system, wherein each mandrel is movable between a working position in which it extends orthogonally to the transport direction and a loading position at which spools of the web material can be loaded on or unloaded from the mandrel; and a system for supplying material to the containers, the feed paths of the transport system extending to said material supply system. 